Protecting or restoring aquatic ecosystems in the face of growing anthropogenic pressures requires an understanding of hydrological and biogeochemical functioning across multiple spatial and temporal scales. Recent technological and methodological advances have vastly increased the number and diversity of hydrological, biogeochemical, and ecological tracers available, providing potentially powerful tools to improve understanding of fundamental problems in ecohydrology, notably: 1. Identifying spatially explicit flowpaths, 2. Quantifying water residence time, and 3. Quantifying and localizing biogeochemical transformation. In this review, we synthesize the history of hydrological and biogeochemical theory, summarize modem tracer methods, and discuss how improved understanding of flowpath, residence time, and biogeochemical transformation can help ecohydrology move beyond description of site-specific heterogeneity. We focus on using multiple tracers with contrasting characteristics (crossing proxies) to infer ecosystem functioning across multiple scales. Specifically, we present how crossed proxies could test recent ecohydrological theory, combining the concepts of hotspots and hot moments with the Damkohler number in what we call the HotDam framework.

As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%-85% of permafrost carbon release can still be avoided if human emissions are actively reduced.

Mercury (Hg) deposited from emissions or from local contamination, can have serious health effects on humans and wildlife. Traditionally, Hg has been seen as a threat to aquatic wildlife, because of its conversion in suboxic conditions into bioavailable methylmercury (MeHg), but it can also threaten contaminated terrestrial ecosystems. In Asia, rice paddies in particular may be sensitive ecosystems. Earthworms are soil-dwelling organisms that have been used as indicators of Hg bioavailability; however, the MeHg concentrations they accumulate in rice paddy environments are not well known. Earthworm and soil samples were collected from rice paddies at progressive distances from abandoned mercury mines in Guizhou, China, and at control sites without a history of Hg mining. Total Hg (THg) and MeHg concentrations declined in soil and earthworms as distance increased from the mines, but the percentage of THg that was MeHg, and the bioaccumulation factors in earthworms, increased over this gradient. This escalation in methylation and the incursion of MeHg into earthworms may be influenced by more acidic soil conditions and higher organic content further from the mines. In areas where the source of Hg is deposition, especially in water-logged and acidic rice paddy soil, earthworms may biomagnify MeHg more than was previously reported. It is emphasized that rice paddy environments affected by acidifying deposition may be widely dispersed throughout Asia.

Currently, there are 428 areas contaminated with chlorinated solvents in Sweden. These substances have been used in Sweden’s industry as degreasing agents and solvents.Chlorinated solvents are more difficult to investigate and remediate compared to petroleum hydrocarbons, due to their complicated distribution in different media. Hence, it is important to increase the knowledge of remediation of chlorinated solvents. The remediation technology excavation is frequently used in Sweden for contaminated areas. Excavation means that soil is dug up and transported to treatment or landfills sites. Due to its climate impact, the use of more sustainable remediation technologies should be increased.

This thesis aimed to evaluate in situ remediation technologies for soil and groundwater contaminated with chlorinated solvents with respect to functionality, sustainability, time and cost aspects. Furthermore, this thesis aimed to investigate which technologies are best suited for Swedish conditions. To evaluate suitability and functionality of remediation technologies,all technologies were described and a case study of five areas in Sweden contaminated with chlorinated solvents was conducted. The contaminant situation and site-specific conditions were described for each area. Thereafter, the evaluation and choice of remediation technology and remediation result were presented. The technologies studied in the case study were two types of chemical reduction, multi-phase extraction, biostimulation and thermal treatment.The five projects were then assessed using the Swedish Geotechnical Institute’s decision support tool for remediation technologies, SAMLA. The technologies were rated in SAMLA according to criteria related to environmental factors, social factors and costs. Furthermore,the remediation technologies were evaluated based on their strengths and limitations with respect to Swedish conditions, such as geology, climate and geochemistry. They were also evaluated based on their strengths and limitations according to implementation areas, cost,remediation time, energy consumption and use in Sweden.The assessment of the five projects in SAMLA produced similar results compared to previously conducted risk evaluations. The technologies that were chosen based on the risk evaluations were also rated highest in SAMLA. The choice of technology for each project was based on conditions for the area, such as geology and existing buildings. Conclusions were drawn indicating that all technologies can be implemented in Sweden with respect to geological conditions. However, site-specific conditions, such as high groundwater flow and heterogeneous soil, limit the implementation of a specific technology. Moreover, other sitespecific conditions than those already discussed have to be considered, for instance buildings or future exploitation. Future development of in situ remediation technologies may focus on implementation of a certain type of geology (highly permeable soils), where chlorinated solvents may be found more frequently.

In the western part of the Philippines, in the Palawan province, studies have shown that large quantities of mercury are spread to the surrounding area during heavy rainfall. In addition, mercury is spread to rice fields and bioaccumulated in marine fish and seafood. The mercury originates from the abandoned Palawan Quicksilver Mine. Since mercury is toxic for the human body and new studies have shown that mercury accumulates in rice, it is important to investigate human exposure from mercury in rice.

This project investigates the total amount of mercury and methylmercury (MeHg) accumulated in rice, soil and water from four different rice fields in Palawan. The soil samples have been taken directly from the fields and water samples have been taken from nearby streams and springs. Rice grains harvested earlier this year from the same fields have been collected from farmers. The soil, water and rice samples were analyzed in Manila and rice samples were as well analyzed in Sweden and China. Furthermore, this project contains a dietary survey and calculation of daily exposure values of MeHg. The survey investigates how often people eat fish and rice and if they have dental amalgam. It also investigates possible health problems related to mercury exposure from rice and fish consumption.

The analyses from China show that rice samples from all barangays contain total mercury and MeHg. Analyses from Sweden also show that rice from the barangays contains total mercury but the levels were found to be higher than the ones analyzed in China. Furthermore, the health problems found in the diet survey were hard to relate to mercury exposure from rice since the health problems can be caused by other factors. When calculating daily exposure values, the values were found to be as high as the recommended maximum acceptable daily intake in one of the barangays. There might therefore be a risk of eating rice from these four barangays. It is important to consider that these daily exposure values were only based on MeHg exposure from rice consumption, not taking dental amalgam and fish consumption into consideration. This means that the daily exposure values might be even higher than the ones calculated in this study.

This paper presents 10 recommendations for improving the European Medicines Agency's guidance for environmental risk assessment of human pharmaceutical products. The recommendations are based on up-to-date, available science in combination with experiences from other chemical frameworks such as the REACH-legislation for industrial chemicals. The recommendations concern: expanding the scope of the current guideline; requirements to assess the risk for development of antibiotic resistance; jointly performed assessments; refinement of the test proposal; mixture toxicity assessments on active pharmaceutical ingredients with similar modes of action; use of all available ecotoxicity studies; mandatory reviews; increased transparency; inclusion of emission data from production; and a risk management option. We believe that implementation of our recommendations would strengthen the protection of the environment and be beneficial to society. Legislation and guidance documents need to be updated at regular intervals in order to incorporate new knowledge from the scientific community. This is particularly important for regulatory documents concerning pharmaceuticals in the environment since this is a research field that has been growing substantially in the last decades.

Phosphorus (P) is often the limiting nutrient in lacustrine and brackish eco-systems, and enhanced input of P into an aquatic system might therefore negatively impact the environment. Because modern waste water manage-ment have reduced external P input to surface waters, internal P loading from the sediment has become one of the main P sources to aquatic ecosys-tems, in which relatively unknown organic P compounds seem to be more active in P recycling than previously thought.

This thesis focus is on improving analysis methods for organic P com-pounds in lacustrine and brackish sediments, as well as determining which of these compounds might be degraded, mobilized and subsequently recycled to the water column and on what temporal scale this occur. In both lacustrine and brackish environments, the most labile P compound was pyrophosphate, followed by different phosphate diesters. Phosphate monoesters were the least labile organic P compounds and degraded the slowest with sediment depth. In regulated lakes, it was shown that pyrophosphate and polyphos-phate compound groups were most related to lake trophic status, thus indi-cating their involvement in P cycling. This thesis also indicates faster P turn-over in sediment from the brackish environment compared to sediment from the lacustrine environment.

A comparison of organic P extraction procedures showed that pre-extraction with EDTA, and NaOH as main extractant, was most efficient for total P extraction. Using buffered sodium dithionite (BD) as a pre-extractant and NaOH as main extractant was most efficient for extracting the presuma-bly most labile organic P compound groups, pyrophosphate and polyphos-phate. Furthermore, it was determined that organic P compounds associated with humic substances were more recalcitrant than other P compounds, that the BD step used in traditional P fractionation might extract phosphate monoesters, and that NMR is a statistically valid method for quantification of organic P compounds in sediment extracts.

Abstract [en]

Phosphorus (P) compounds in three different lake surface sediments were extracted by sequential P extraction and identified by P-31 nuclear magnetic resonance (P-31 NMR) spectroscopy. The extraction procedure primarily discriminates between inorganic P-binding sites but most extraction steps also contained P not reacting (nrP) with the molybdenum complex during P analyses. In all three lakes, the nrP dominated in the NaOH extracts. Nonreactive P from the dystrophic lake was dominated by potentially recalcitrant P groups such as orthophosphate monoesters, while the nrP in the two more productive lakes also contained polyphosphates, pyrophosphate, and organic P groups such as P lipids and DNA-P that may be important in remineralization and recycling to the water column. In addition, polyphosphates showed substantial dynamics in settling seston. The Humic-P pools (P associated with humic acids) showed strong signals of orthophosphate monoesters in all three lakes, which supported the assumption that P-containing humic compounds are indeed recovered in this fraction, although other organic P forms are also present. Thus, in addition to expanding the understanding of which organic P forms that are present in lake sediments, the P-31 NMR technique also demonstrated that the chemical extraction procedure may provide some quantification of recalcitrant versus labile organic P forms.

Abstract [en]

Phosphorus (P) composition in alkaline sediment extracts from three Swedish oligotrophic mountain lakes was investigated using P-31-NMR spectroscopy. Surface sediments from one natural lake and two mature reservoirs, one of which has received nutrient additions over the last 3 years, were compared with respect to biogenic P composition. The results show significant differences in the occurrence of labile and biogenic P species in the sediments of the different systems. The P compound groups that varied most between these three systems were pyrophosphate and polyphosphates, compound groups known to play an important role in sediment P recycling. The content of these compound groups was lowest in the reservoirs and may indicate a coupling between anthropogenic disturbances (i.e., impoundment) to a water system and the availability of labile P species in the sediment. A statistical study was also conducted to determine the accuracy and reliability of using P-31-NMR spectroscopy for quantification of sediment P forms.

Abstract [en]

Phosphorus (P) binding groups were identified in phytoplankton, settling particles, and sediment profiles by 31P NMR spectroscopy from the Swedish mesotrophic Lake Erken. The 31P NMR analysis revealed that polyphosphates and pyrophosphates were abundant in the water column, but rapidly mineralized in the sediment. Orthophosphate monoesters and teichoic acids degraded more slowly than DNA-P, polyphosphates, and P lipids. Humic acids and organic acids from phytoplankton were precipitated from the NaOH extract by acidification and identified by 31P NMR spectroscopy. The precipitated P was significantly more recalcitrant than the P compound groups remaining in solution, but does not constitute a major sink of P as it did not reach a stable concentration with depth, which indicates that it may eventually be degraded. Since P also precipitated from phytoplankton, the origin of humic-P can not be related solely to allochthonous P.

Abstract [en]

The influence of pre-extractant, extractant, and post-extractanton total extracted amounts of P and organic P compound groupsmeasured with 31P nuclear magnetic resonance (31P-NMR) in lacustrinesediment was examined. The main extractants investigated weresodium hydroxide (NaOH) and sodium hydroxide ethylenediaminetetraaceticacid (NaOH-EDTA) with bicarbonate buffered dithionite (BD) orEDTA as pre-extractants. Post extractions were conducted usingeither NaOH or NaOH-EDTA, depending on the main extractant.Results showed that the most efficient combination of extractantsfor total P yield was NaOH with EDTA as pre-extractant, yieldingalmost 50% more than the second best procedure. The P compoundgroups varying the most between the different extraction procedureswere polyphosphates and pyrophosphates. NaOH with BD as pre-extractantwas the most efficient combination for these compound groups.

Environmental changes are predicted to have severe and rapid impacts on polar and alpine regions. At high latitudes/altitudes, cryptogams such as bryophytes and lichens are of great importance in terms of biomass, carbon/nutrient cycling, cover and ecosystem functioning. This seven-year factorial experiment examined the effects of fertilizing and experimental warming on bryophyte and lichen abundance in an alpine meadow and a heath community in subarctic Sweden. The aim was to determine whether shortterm responses (five years) are good predictors of longer-term responses (seven years). Fertilizing and warming had significant negative effects on total and relative abundance of bryophytes and lichens, with the largest and most rapid decline caused by fertilizing and combined fertilizing and warming. Bryophytes decreased most in the alpine meadow community, which was bryophyte-dominated, and lichens decreased most in the heath community, which was lichen-dominated. This was surprising, as the most diverse group in each community was expected to be most resistant to perturbation. Warming alone had a delayed negative impact. Of the 16 species included in statistical analyses, seven were significantly negatively affected. Overall, the impacts of simulated warming on bryophytes and lichens as a whole and on individual species differed in time and magnitude between treatments and plant communities (meadow and heath). This will likely cause changes in the dominance structures over time. These results underscore the importance of longer-term studies to improve the quality of data used in climate change models, as models based on short-term data are poor predictors of long-term responses of bryophytes and lichens.

A decline has been seen in Sweden and Europe when it comes to air pollution the last decades. The decline is partly due to reduced emissions from industries, switching from heating using oil and coal boilers to district heating and better fuel quality. This study evaluates deposition and air concentration measurements made in the vicinity of the pulp and paper industry Korsnäs in Gävle. The measurement series starts at the late 1970s and goes up to year-end 2009/2010. Deposition of dust, sulphate, sodium, calcium and air concentrations of sulphur dioxide and soot were studied. Comparisons were made with Korsnäs environmental measures and emissions during the same time period and with other measurements made in Sweden and Gävleborgs County.

The study showed a decrease in sulphur dioxide concentrations in the air. This fits well with a major reduction of sulphur emissions from the factory area in the early 1990s when installations of treatment plants were made at the largest emission sources of sulphur dioxide. Reducing the sulphur content of fuel oil from Karskär Energi AB, an energy combine owned by Korsnäs in the same factory area, contributed to the decrease during the same time period. Air concentrations of soot showed no downward trend over the years, but were seasonal, with higher average soot concentrations in the winter. This was most likely caused by the burning of fuel oil from both the private sector and Karskär Energi AB. The largest air concentrations did not show higher levels of sulphur dioxide and soot when the mean wind direction was easterly and thus blew from factory area toward the monitoring station but when the wind direction was southwesterly and blew from inland. The total dust and calcium deposition showed no decline but had higher average measured levels in the summer. Sulphate deposition showed high levels during the late 1980s but has thereafter decreased. The sodium deposition decreased a little during the time period. No clear connection was found between deposition/air concentrations and emissions from the factory area when the data series were sorted by wind direction, wind speed and after the summer and winter months. Depositions and air concentrations were not higher except for sulphur dioxide when the comparison was made with other measurements in Sweden and Gävleborg County. All measurements were below the then current national limits.

Falu copper mine was Sweden’s oldest mine industry which lasted for almost a thousand years. Throughout the history its area has been vastly contaminated by sulfur oxide. The contaminations has created the mining area to an environmental risk zone which has the ability to spread out into the Falu River. The river has its connections to the Dal River which is discharging towards its mouth in the Baltic Sea. In the year 1968 the first measurement from the polluted Falu River took place. Its metal content came from the mining area, although the decontamination expenses were too high for the running company Stora Kopparbergs Bergsslag AB to pay which then led to conflicts with the Environmental Protection Agency of Sweden on terms none of them could agree on. It was not until the year 1983 when they both agreed on a cooperation which contained of continuing measurements until a suffi-cient decontamination method could be applied. The cooperation was named Projekt Falu gruva. The first obligation was to improve the sewage plant in Främby by con-necting the contaminated water from the mining area with the waste water though a chemical treatment. In the year 1987 the treatment successfully began and the same year the Swedish government financed a delegation, called Dalälvsdelegationen, and its purpose was to decontaminate the pollutions along the Dal River. The delegation’s research led to three reports which contained the areas involved in the river’s pollu-tion as well how the mining area would be treated. In 1992 the Country Administra-tive Board of Dalarna, the Environmental Authority of Falun Municipality, the Environ-mental Protection Agency of Sweden and Stora Kopparbergs Bergsslag AB began cooperation in order to treat the polluted area of Falu copper mine. This cooperation became a project called Faluprojektet. The project consisted of three decontamina-tion priorities with different treatments in the area. The first decontamination priority resulted in a reducing amount of the polluted mining water by 80 % in the Falu River. The second and the third decontamination priorities had some issues during its treat-ment due to new environmental laws influenced in 1999 and the recognition from UNESCO as this area was since 2001 a world cultural heritage. Both the law and the recognition stated that it was forbidden to remove the waste on the ground from the area since it was a part of the cultural protection. This meant the waste was removed closer to the mine pit and became part of a slower and natural hydrological treatment which caused the sulfur dioxide penetrating into the ground. By doing this type pf treatment it reflects upon the environmental quality goals which Sweden is aiming for in order to reach for sustainable development.

The health of the Baltic Sea is negatively affected by hazardous substances such as metals and persistent organic pollutants (POPs), which include legacy pollutants that were banned decades ago, but still circulate in the ecosystem. Elevated levels of legacy pollutants, identified by HELCOM as key hazardous substances, have been found in accumulations of fibrous sediments, so-called fiberbanks and fiber-rich sediments, which derive from old pulp mills along the Swedish north coast. The fiberbanks are deposited in shallow water and bathymetrical models show evidence of their erosion, potentially caused by propeller wash, submarine landslides and gas ebullition. This thesis addresses the potential dispersal of key substances from three fiberbank sites located in a non-tidal Swedish estuary, in which metals and POPs are present in concentrations that may pose a risk for benthic organisms. Metals and POPs are partitioned to organic material and, as expected, show the highest partitioning coefficients (KD) in fiberbanks that have higher TOC levels compared to adjacent areas with fiber-rich sediments (natural clay sediments mixed up with fibers) or relatively unaffected postglacial clays. However, many analytes were found to be present in quantifiable concentrations in pore water, which indicates diffusion of substances from the solid phase to the aqueous phase. To assess the dispersive influence of an abrupt erosional event on dispersion, metals were measured in undisturbed bottom water and in bottom water disturbed by artificial re-suspension of fibrous sediments. The bioavailable, dissolved fraction of metals decreased in bottom water after re-suspension, probably due to the particle concentration effect. In contrast, the total concentrations of metals and number of quantifiable metals increased with particle concentration caused by re-suspension. At one station, the total concentration of chromium (Cr) was elevated to a level where it may lower the ecological status of the water body during periods of substantial erosion (e.g. spring floods or submarine landslides). Analyses of disturbed bottom water revealed, however, that minerogenic particles were preferentially re-suspended compared to organic. This suggests that physical erosion and re-suspension of fiberbank sediments might have a larger effect on dispersal of metals than on POPs.

Industrial emissions can impact aquatic environments and unregulated discharges from pulp and paper factories have resulted in deposits of cellulose fiber along the Swedish coast. These deposits are contaminated by metals, but due to their unique fibrous character the extent of sorption and dispersal of the metals is unclear. Fibrous sediments were sampled at two sites in the Ångermanälven river estuary, Sweden. The partitioning of metals between the sediment, pore water and bottom water was investigated and the degree of bioavailability was evaluated. The levels of metals in the sediment were high in fibrous or offshore samples, depending on the metal, whereas the levels of dissolved metals in pore water were low or below the limit of quantification. Partition coefficients (KD) showed that sorption to the sediment was stronger at one of the fibrous sites, possibly related to the type and size of organic matter. Undisturbed bottom water samples contained low levels of both dissolved and particle bound metals, but when comparing measured metal concentrations to threshold values of ecological status and ecotoxicological assessment criteria, both sediments and bottom water may be detrimental to living organisms. In-situ re-suspension experiments showed that the concentrations of particle bound metals increased whereas the dissolved concentrations decreased. The analyzed metals are probably retained by the solid phases of the fibrous sediment or adsorbed to particles in the water, reducing their bioavailability.

The activity of open-vent volcanoes with an active lava-lake, such as Nyiragongo, is characterized by persistent degassing, thus continuous monitoring of the rate, volume and fate of their gas emissions is of great importance to understand their geophysical state and their potential impact. We report results of SO2 emission measurements from Nyiragongo conducted between 2004 and 2012 with a network of ground-based scanning-DOAS (Differential Optical Absorption Spectroscopy) remote sensors. The mean SO2 emission rate is found to be 13 ± 9 kg s−1, similar to that observed in 1959. Daily emission rate has a distribution close to log-normal and presents large inter-day variability, reflecting the dynamics of percolation of magma batches of heterogeneous size distribution and changes in the effective permeability of the lava lake. The degassed S content is found to be between 1000 and 2000 ppm from these measurements and the reported magma flow rates sustaining the lava lake. The inter-annual trend and plume height statistics indicate stability of a quiescently degassing lava lake during the period of study.

Stormwater is the name for rainwater and snowmelt runoff from impervious surfaces in the urban environment. This water often carries large amounts of pollutants such as heavy metals, nutrients, and oil-related substances, which can cause great damage if they reach the receiving waters. To clean the storm water and thus reduce the pollution load, more and more open storm water systems are being built, such as wetlands and ponds. Studies have shown that these systems have high pollutant removal efficiency and are cost effective. Knowledge of how these systems work and how they best are evaluated is limited.

“Kungsängsdammen” near Uppsala is a newly constructed stormwater facility that is designed to clean and retard stormwater from the industrial and commercial area Boländerna. This thesis aims to investigate the purification function of the facility. Flow proportional sampling was carried out at the inlet and outlet for 8 weeks. Substances that were analyzed were nutrients P and N, suspended solids, heavy metals As, Cd, Co, Cr, Cu, Mo, Ni, Pb, V, Zn and petroleum hydrocarbons. On some occasions, the petroleum-related organic parameters PAHs, octyl and nonylphenols and tributyltin were analyzed. Flow proportional sampling is recommended to determine the efficiency of a stormwater pond, but the problem is that it takes much time and considerable resources. In addition to this method, additional measurements were carried out with sediment traps, and a calculation of pollution load at the inlet with the program StormTac.

The flow proportional sampling showed that the “Kungsängsdammen” pond-, functions well as a treatment facility for pollutions. Suspended solids, nutrients and heavy metals are separated effectively and the outlet concentrations for these substances were below proposed guideline values. This is observed, despite the fact that zinc, copper, nitrogen and suspended solids had intake concentrations above the guideline values. Flow calculations showed that the bypass flow is important when estimating the pollutant removal efficiency. For organic compounds, tributyltin was measured at concentrations above the Environmental Quality Standards (EQS) for surface water both at the inlet and outlet. The inlet concentrations that were calculated in StormTac were consistent with the results of the flow proportional sampling for heavy metals and nutrients. Moreover, the investigation of sediments showed that sedimentation occurs mainly in the ditch before the pond and at the inlet to the pond. The ditch is in need of cleansing, because of the risk of sediment being washed away during high flows.

The flow proportional sampling showed that the “Kungsängsdammen” pond-, functions wellas a treatment facility for pollutions. Suspended solids, nutrients and heavy metals are separated effectively and the outlet concentrations for these substances were below proposedguideline values. This is observed, despite the fact that zinc, copper, nitrogen and suspended solids had intake concentrations above the guideline values. Flow calculations showed that the bypass flow is important when estimating the pollutant removal efficiency. For organiccompounds, tributyltin was measured at concentrations above the Environmental Quality Standards (EQS) for surface water both at the inlet and outlet. The inlet concentrations that were calculated in StormTac were consistent with the results of the flow proportional sampling for heavy metals and nutrients. Moreover, the investigation of sediments showedthat sedimentation occurs mainly in the ditch before the pond and at the inlet to the pond. The ditch is in need of cleansing, because of the risk of sediment being washed away during high flows.

The degradation and transformation of organic carbon (C) in inland waters result in significant CO2 emissions from inland waters. Even though most of the C in inland waters occurs as dissolved organic carbon (DOC), studies on particulate organic carbon (POC) and how it influences the overall reactivity of organic C in transport are still scarce. We sampled 30 aquatic ecosystems following an aquatic continuum including peat surface waters, streams, rivers, and lakes. We report DOC and POC degradation rates, relate degradation patterns to environmental data across these systems, and present qualitative changes in dissolved organic matter and particulate organic matter during degradation. Microbial degradation rates of POC were approximately 15 times higher compared to degradation of DOC, with POC half-lives of only 17 +/- 3 (mean +/- SE) days across all sampled aquatic ecosystems. Rapid POC decay was accompanied by a shift in particulate C: N ratios, whereas dissolved organic matter composition did not change at the time scale of incubations. The faster degradation of the POC implies a constant replenishment to sustain natural POC concentrations. We suggest that degradation of organic matter transported through the inland water continuum might occur to a large extent via transition of DOC into more rapidly cycling POC in nature, for example, triggered by light. In this way, particles would be a dominant pool of organic C processing across the boreal aquatic continuum, partially sustained by replenishment via flocculation of DOC.

Excess nitrogen fertiliser in agricultural soils might be leached to streams and converted to the greenhouse gas nitrous oxide (N2O). To assess the importance of N2O emissions from agricultural streams, concentration dynamics and emissions N2O emissions in streams were investigated in a 32 km2 lowland agricultural catchment located in Sweden. Dissolved N2O concentration was measured at nine occasions between December 2014 and August 2015 at nine stream stations. The stream stations represented sub-catchments with different land use characteristics with agricultural land use ranging from 0 to 63% of the area. Stream N2O percentage saturation ranged 40-2701% and showed large spatial and temporal variations. Statistical analysis using mixed models revealed that N2O concentration was significantly linked to nitrate concentration in the stream water, to the percentage arable land in the sub catchments as well as to the stream water discharge. Using two empirical equations to estimate the N2O emissions showed that streams were generally a source of N2O to the atmosphere (mean 108 and 175 mu g N m(-2) h(-1) with first and second equation). The catchment scale estimate of N2O stream emissions was compared to the estimate obtained using IPCC guidelines linking N fertilisation inputs and leaching to N2O emissions. The comparison suggested that N2O stream emission calculated using the IPCC methodology might be underestimated. A coarse estimate suggests that N2O stream emissions represent about 4% of the total N2O emissions from N-fertiliser at the catchment scale. Hence while streams covered only 0.1% of the catchment area they were of disproportionate importance as a source of N2O to the atmosphere.

The goal of this master thesis project was to develop computer models of some plausiblepretreatment techniques and to assess the potential benefits/costs of using pretreatment andanaerobic digestion for waste management of organic waste from a system perspective. Forthis purpose a computer program called ORWARE has been used. ORWARE (organic wasteresearch) is a program for making life cycle assessments of waste management. As the mainpart of the project work the ORWARE system has been provided with three new models ofpretreatment techniques. The additions consist of: One model of pretreatment with ultrasound,one model of thermal hydrolysis and one model of a screw press. All three technologies hadthe potential to deal with technical hindrances of treating certain waste types with anaerobicdigestion.With ORWARE, life cycle assessment was made by simulations of various wastemanagement scenarios. A total of nine scenarios were simulated for the waste management ofthree different types of wastes: Bio sludge, fibre sludge and food waste, with three scenariosfor each waste type. Bio sludge is microbial sludge from biological waste water treatment.Fibre sludge is lignocellulosic sludge mainly from the pulp and paper industries. Food wasteis generally considered to be the unwanted part of food from households, restaurants and foodindustry.Three primary waste management scenarios, one scenario for each waste type, which includedpretreatment and anaerobic digestion, were simulated. There was a “bio sludge scenario” withultrasonication pretreatment, a “fibre sludge scenario” with thermal hydrolysis pretreatment(THP) and a “food waste scenario” with screw press pretreatment. The rest of the ninescenarios were assessed as comparative references to the three primary ones. These scenariosrepresented conventional methods of waste management or variations of the primaryscenarios.The resulting life cycle assessments show that anaerobic digestion of some organicwastes produces about the same amount of greenhouse gases, acidifying pollutants andeutrophying pollutants as incineration does (where the heat from incineration is made useful).The biggest downside of the anaerobic digestion waste management process is the electricityuse needed for pretreatment and for heating the anaerobic digestion. An electricity cost that inthis case is assumed to be provided through coal power, which is a common assumption whenassessing the impact of margin power utilization in life cycle assessment. If that assumptioncould instead be that the electricity is provided by a less polluting power source, the anaerobicdigestion alternative could lessen the overall pollution since the methane is commonly used asa renewable substitute for fossil fuels.In this master thesis project the ecological and economical benefits and costs of managingorganic waste through pretreatment and anaerobic digestion were assessed. These benefits andcosts were compared to conventional waste management in Sweden. The comparison showsthat anaerobic digestion of organic waste is beneficial for reduction of global warming butlikely has a greater economical cost than the conventional methods, e.g. incineration.

Stress responsiveness differs between individuals and is often categorized into different stress coping styles. Using these stress coping styles for selection in fish farming could be beneficial, since stress is one main factor affecting welfare. In Arctic charr (Salvelinus alpinus) carotenoid pigmentation is associated with stress responsiveness and stress coping styles. Thus this could be an important tool to use for selection of stress resilient charr. However, anaesthetics seem to affect carotenoid pigmentation, and it would be better if the method for selection could be implemented during normal maintenance, which usually includes anaesthetics. Therefore, this study investigated how the use of anaesthetics affected carotenoid pigmentation, i.e. number of spots, over time compared to no-anaesthetic treatment. Additionally, the stress indicators monoamines and glucocorticoids were investigated. The results indicate that the anaesthetic MS-222 affects number of spots on the right side. This anaesthetic also increased dopaminergic activity in the telencephalon. Both brain dopaminergic and serotonergic activity was associated with spottiness. Further, behaviour during anaesthetization was associated with spots on the left side, but not the right side. Repetition of the same treatment seemed to affect spot numbers on the right side. In conclusion, this study shows that inducing stress in charr affects the carotenoid spots. Thus, it is possible to use anaesthetics when evaluating spottiness although careful planning is needed.

Soils harbour some of the most diverse microbiomes on Earth and are essential for both nutrient cycling and carbon storage. To understand soil functioning, it is necessary to model the global distribution patterns and functional gene repertoires of soil microorganisms, as well as the biotic and environmental associations between the diversity and structure of both bacterial and fungal soil communities1-4. Here we show, by leveraging metagenomics and metabarcoding of global topsoil samples (189 sites, 7,560 subsamples), that bacterial, but not fungal, genetic diversity is highest in temperate habitats and that microbial gene composition varies more strongly with environmental variables than with geographic distance. We demonstrate that fungi and bacteria show global niche differentiation that is associated with contrasting diversity responses to precipitation and soil pH. Furthermore, we provide evidence for strong bacterial-fungal antagonism, inferred from antibiotic-resistance genes, in topsoil and ocean habitats, indicating the substantial role of biotic interactions in shaping microbial communities. Our results suggest that both competition and environmental filtering affect the abundance, composition and encoded gene functions of bacterial and fungal communities, indicating that the relative contributions of these microorganisms to global nutrient cycling varies spatially.

The Baffin Island region in the eastern Canadian Arctic has recently experienced a rapid warming, possibly unprecedented in millennia. To investigate theresponse of freshwater environments to this warming and place it in a secular perspective, we analyzed a 90-cm-long sediment core from Nettilling Lake,the largest lake of the Canadian Arctic Archipelago. The core was taken from a part of the lake basin that receives meltwater and sediment inputs from thenearby Penny Ice Cap. The core time scale, established using 137Cs and palaeomagnetic techniques, spans an estimated 600 years. A multi-proxy approachwas used to document changes in the physical, chemical, and biological properties of the sediments. We found evidence for a relatively warm period (mid/late 15th century to mid/late 16th century) during the early part of the ‘Little Ice Age’ (LIA), characterized by high sedimentation rates and laminations.This was followed by colder, drier, and windier conditions corresponding to the coldest phase of LIA and coinciding with the latest and most extensiveperiod of regional ice cap expansion (early 16th to late 19th centuries). A rapid warming occurred at the beginning of the 20th century. Variations intitanium (Ti) content in the core, a proxy for detrital sediment inputs, showed good agreement with reconstructed secular variations in summer meltrates on Penny Ice Cap between the mid-14th century and the present-day, providing supporting evidence for a climatic–hydrological connection betweenthe ice cap and Nettilling Lake.

Traces of active pharmaceutical ingredients (APIs) and other chemicals are demonstrated in effluents from sewage treatment plants (STPs) and they may affect quality of surface water and eventually drinking water. Treatment of effluents with granular activated carbon (GAC) or ozone to improve removal of APIs and other contaminants was evaluated at two Swedish STPs, Kappala and Uppsala (88 and 103 APIs analyzed). Biomarker responses in rainbow trout exposed to regular and additionally treated effluents were determined. GAC and ozone treatment removed 87-95% of the total concentrations of APIs detected. In Kappala, GAC removed 20 and ozonation (7 g O-3/m(3)) 21 of 24 APIs detected in regular effluent. In Uppsala, GAC removed 25 and ozonation (5.4 g O-3/m(3)) 15 of 25 APIs detected in effluent. GAC and ozonation also reduced biomarker responses caused by unidentified pollutants in STP effluent water. Elevated ethoxyresorufin-O-deethylase (EROD) activity in gills was observed in fish exposed to effluent in both STPs. Gene expression analysis carried out in Kappala showed increased concentrations of cytochrome P450 (CYP1A5 and CYP1C3) transcripts in gills and of CYP1As in liver of fish exposed to effluent. In fish exposed to GAC- or ozone-treated effluent water, gill EROD activity and expression of CYP1As and CYP1C3 in gills and liver were generally equal to or below levels in fish held in tap water. The joint application of chemical analysis and sensitive biomarkers proved useful for evaluating contaminant removal in STPs with new technologies.

Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Educational Sciences, Department of Education. Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Educational Sciences, SWEDESD - The Swedish International Centre of Education for Sustainable Development.

Living systems in general and urban structures in particular finda large number of ways to make themselves sustainable. In thischapter the five properties for sustainability applied to the modelneighbourhood Hågaby is described, and discussed as a generaltheory for sustainability of urban environments.

Methods to demonstrate resources for sustainability in the modelarea Hågaby are described. Physical, economic, organisational,human and cultural resources are studied using a mix of quantitativeand qualitative assessments.

The results of the first four years of development (1996-2000) ofthe model project Hågaby are reported. Data include quantitativeanalysis of a series of practical projects such as solar energy,wastewater treatment, household composting, as well as socialand economic aspects of a sustainable community life.

In Sweden there are around 25,000 contaminated areas classified as a risk for human health or the environment, and even more potentially contaminated areas. The Swedish Environmental Protection Agency has developed generic guideline values for hazardous substances. Contamination levels exceeding the guideline values indicate a large risk for human health or the environment and that there is a need to remediate the site. A frequently used and expensive aftertreatment is excavation and removal of contaminated soil. Therefore, there is an interest to develop easy applicable methods for site-specific risk assessment with the purpose to protect the soil environment and its functions. Microorganisms involved in the nitrogen cycle perform key functions in soil. Several studies indicate that the abundance and activity of N-cycling microorganisms are sensitive to various soil pollution.

Within the research project APPLICERA, a lysimeter experiment was conducted with two different soil types (acidic sandy soil and slightly alkaline sandy loam) and different contamination levels of copper and PAH. The contamination levels corresponded to generic guideline values for sensitive land-use (KM), less sensitive land-use (MKM) and 3xMKM. Soil samples were taken at three times during a period of 16 months. The aim of this master thesis was to investigate nitrifying microorganism potential as indicators for altered soil functioning in contaminated soil. Ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and the nitrite-oxidizing bacteria genera Nitrospira and Nitrobacter has been quantified in soil samples with the different treatments. Measurements of the potential ammonia oxidation (PAO) have been performed in soil from the last sample taking.

The abundance of the nitrifying microorganisms was in general higher in the slightly alkaline sandy loam soil. Over time there was a decrease in AOA abundance for the highest concentration of copper and PAH, most pronounced in the acidic sandy soil. Also, a decrease in the abundance of Nitrospira in soil contaminated with PAHs could be seen for both soil types. In copper contaminated soil a distinct decrease in the abundance of Nitrospira could only be seen in the acidic sandy soil. The abundance of AOB and Nitrobacter did not show any obvious pattern for different contamination levels or over time. The difference in abundance of nitrifying microorganisms between the soil types suggests that the soil’s chemical and physical characteristics as well as the bioavailability of the contaminant affected their abundance. A significant decrease in PAO could be seen for the highest contamination level of copper for both soil types, but for the PAH contaminated soil PAO decreased only in the acidic sandy soil. These results suggest that the abundance of AOA and Nitrospira seems to have greatest potential as general indicators for altered soil functioning. However, improved activity measurements are needed to gain greater insight into the soil N-cycle functioning in contaminated soils.

Endosulfan is an organochlorine pesticide used in agriculture for a wide range of crops. Endosulfan concentrations of up to 0.7 mg/L can be found in ponds and streams near sprayed agricultural fields. We investigated the short-term toxicity of endosulfan in common toad (Bufo bufo) tadpoles after 24, 48, and 96 h of exposure. Acute toxicity was evaluated at nominal concentrations ranging from 0.01 to 0.6 mg/L: concentrations that could be found after the application of pesticide. Our results show that 0.43 mg/L of endosulfan caused 50% mortality (LC(50)). The effects of a sublethal endosulfan concentration (0.2mg/L) on gill apparatus morphology were evaluated by scanning and transmission electron microscopy. Immunohistochemical methods were also applied to detect the expression pattern of the inducible isoform of nitric oxide synthase (iNOS) in the gills using the confocal laser scanner microscope. Exposure to 0.2mg/L of endosulfan caused an apparent increase in mucus production, the occurrence of secretory vesicles and lamellar bodies, a widening of intercellular spaces and additionally there was evidence of an inflammatory response in the gill apparatus. The morphological alterations occurred after 24h and were more pronounced after 48 and 96 h of exposure. Altered morphology and increased mucus secretion indicate impaired gas exchange and osmoregulation in the gills. In addition, there was an increase of iNOS expression after 24 and 48 h which may reflect hypoxia and inflammation in the gill epithelium. Our results clearly indicate that short-term exposure to a sublethal concentration of endosulfan, near the high end of the environmental range, disrupts gill morphology and function in B. bufo tadpoles.

In Kampala, the capital of Uganda, there is an extensive use of water mixed with wastewater for irrigation of crops. The water is taken from Nakivubo channel that flows through the centre of the city, and since the wastewater treatment in the city is insufficient, the channel water might contain pharmaceuticals that are spread to the farmlands and the crops that are grown in Nakivubo wetland. The aim of this Master’s thesis was to examine the concentration of some selected pharmaceuticals in water, soil and crop samples collected from Nakivubo channel and the area surrounding it. The water was analysed from five measurement points in the Nakivubo channel and Lake Victoria. The solid samples comprised of soil and crops collected from cocoyam, maize and sugar cane fields in the Nakivubo area. The pharmaceutical analyses were carried out through pharmaceutical extraction (solid phase extraction and QuEChERS) and the use of LC-MS (liquid chromatography combined with mass spectrometry). The capacities of the water and soil to reduce pharmaceuticals were analysed and a risk assessment was made in order to determine if it was harmful to drink water from Lake Victoria, the source of drinking water for Kampala, or to eat the crops that were grown in the wetland.

A majority of the pharmaceuticals studied (42 substances) were detected in the water samples (29 substances). The most common pharmaceuticals detected in the water were atenolol, carbamazepine, sulfamethoxazole and trimethoprim. The antibiotics trimethoprim and sulfamethoxazole showed the highest average concentrations in the various water samples (26100 ng/l and 3790 ng/l respectively). Fewer pharmaceuticals were detected in the soil compared to the water (11 substances). The pharmaceuticals most frequently found in the soil were carbamazepine and pyrimethamine and they also had the highest average concentrations along with trimethoprim, 4.6-9.4 ng/g, 8.4-14.0 ng/g and 39.6 ng/g, respectively. No pharmaceuticals could be detected in the edible part of maize and sugar cane, but lidocaine, trimethoprim and pyrimethamine were found in detectable concentrations in the yam (on average 1.2-2.2 ng/g). A significant negative correlation could be found between carbamazepine and total suspended solids (TSS) in the water (linear regression: y = -0.67x +3.98, R2 = 0.35, p < 0.05, n = 14). The risk assessment showed that the concentrations found in the yam and water in Lake Victoria together with the average daily intake of yam and drinking water was not hazardous to the people of Kampala. However, eating more than 0.5 kg of yam daily might pose a risk with regards to pyrimethamine. On the other hand, the concentration in the yam might decrease when it is boiled, and this has not been accounted for.

Recreational fishing is an important activity that delivers substantial social and economic values. Proper management of recreational fisheries relies on information about resource use and associated values by different fishers, but such information is rare, particularly for open access fisheries. In this study a survey of 471 fishers on the Swedish island of Gotland in the Baltic Sea, assessed catches, proportion of catch-and-release (C&R), and economic value (expenditures and willingness to pay, WTP) of sea trout fishing in 2015-2016. Data was analysed in relation to gear used (fly and spin angling, nets and mixed fishery) and fisher connection to fishing site (permanent and temporary residents, Swedish and international tourists). There were marginal differences in daily catch rates, but significant differences in effort and annual catches between different fishers, with resident fishers having the highest catches. Anglers had 86% C&R rates, and fly fishers (> 95%) differed significantly from other anglers. Anglers, particularly fly fishers and fishing tourists, had much higher expenditures per year, fish caught and fish kept compared to net fishers. WTP before refraining from fishing, for doubling of fish supply and for potential fishing license was also highest among anglers. Our findings are discussed in terms of distinguishing characteristics for different types of recreational fishers. Fishing efforts, economic values and the need for further studies are also outlined in the context of fisheries and tourism management.

Engaging civil society in conservation activities is an important complementary strategy to counteract ongoing biodiversity decline and loss of ecosystem services. Since 2011, the Swedish Anglers Association (SAA) has cooperated with landowners to restore wetlands nationwide. We investigated factors that enabled or hindered civil society-led wetland restoration in Sweden through interviews and surveys with the SAA's project leaders and landowners. Principal internal and external factors contributing to the project's implementation included: flexibility and adaptive management of its leadership; support from authorities and policies; the good reputation of the SAA team; and landowners' willingness to cooperate. The latter was linked to their feelings of environmental responsibility, the low investment required by them, and expectations of some benefits. We discuss the need to enable adaptive management in environmental management projects, adjust existing policies to their needs, and re-think funding strategies to consider the long-term nature of such projects.

During pulp and papermaking process a huge amount of water is used. The wastewater contains a large amount of pollutants and has to be treated before it reaches the recipient. In March 2004 a new bleaching plant was started up at SCA Graphic Sundsvall AB, Ortviken’s paper mill using peroxide. The production of bleached thermo mechanical pulp and thus the load to the wastewater plant increased. During bleaching substances dissolve from the pulp and the amount of COD in the wastewater increase. To keep the efficiency of chemical and biological oxygen demand (COD, BOD) removal, the aerated lagoon is supplied by liquid oxygen. In November the same year a new pre-step including a pre-aeration, carrier and selector step was added to the existing wastewater plant. The COD-loading to the lagoon decreased and the supply of liquid oxygen was reduced.

This master thesis has been carried out at SCA Graphic Research AB, Sundsvall. The aim was to chemically characterize the wastewater with focus on the composition of carbohydrates, lignin and extractives and its influence on the biodegradability. Measurements have been carried out on total samples, suspended solids, colloidal and dissolved substances using GF/A and ultra filtration. Measurements were performed on process water from the bleaching plant and on water during the wastewater treatment process. The results show that the chemical composition of dissolved substances has a larger impact on the biodegradability than the total amount of COD. A large amount of lignin will make the wastewater harder to degrade. Suspended solids have lower biodegradability compared to the dissolved fraction. Analyzes of suspended material from the bleaching plant show a relative composition of around 41 % lignin. Analyzes done before on the dissolved fraction show a composition of 29 %. It seems that a larger amount of lignin is represented in suspended solids compared to the dissolved fraction. This can explain the low biodegradability, combined with the theory that the suspended solids are less accessible for the microorganisms. To reduce the outgoing COD the incoming flow of dissolved lignin and suspended solids to the active sludge plant has to decrease. COD in the outgoing wastewater to the recipient consists of around 90 % lignin. Extractives as saturated fatty acids, palmitic and stearic acid plus lignans (which is interpreted as a byproduct from lignin degradation) do not degrade remarkable during wastewater treatment. Flocculation of COD is one way to reduce the discharge to the recipient. Addition of 2,6 g/l PAX-18 (a high charged aluminum complex) to the wastewater from the bleaching plant gives a reduction of 40 % COD and 50 % lignin in laboratory scale and it is recommended to study further. Time related studies of BOD show that the microorganisms need five days to degrade organic material and the hydraulic retention time in the aerated lagoon has to be guaranteed.

This study investigated the i) kinetics, and ii) proportion of photolysis of 30 relatively stable active pharmaceutical ingredients (APIs) during artificial UV irradiation for 28 d in ammonium acetate buffer, filtered and unfiltered river water. Buffer was included to control removal kinetics under stable pH conditions and without particulate matter. Dark controls were used to determine removal due to other processes than photolysis and calculate the proportion of photolysis of the total removal. The removal of each API in each matrix was determined using online solid phase extraction/liquid chromatography tandem mass spectrometry (online SPE/LC-MS/MS). Most APIs transformed during the 28 d of UV irradiation and the dark controls showed that photolysis was the major removal process for the majority of the APIs studied. The half-lives ranged from 6 h (amitriptyline) in unfiltered river water to 884 h (37 d, carbamazepine) in buffer. In unfiltered river water, the proportion of APIs with short half-lives (<48 h) was much higher (29%) than in the other matrices (4%), probably due to additional organic carbon, which could have promoted indirect photolysis. Furthermore, two APIs, memantine and fluconazole, were stable in all three matrices, while alprazolam was stable in buffer and unfiltered river water and four additional APIs were stable in buffer. Considering the relatively long-term UV-exposure, this study enabled the investigation of environmentally relevant half-lives in natural waters. Many APIs showed high persistence, which is environmentally concerning and emphasizes the importance of further studies on their environmental fate and effects.

Chlor-alkali plants using mercury (Hg) cell technology are acute point sources of Hg pollution in the aquatic environment. While there have been recent efforts to reduce the use of Hg cells, some of the emitted Hg can be transformed to neurotoxic methylmercury (MeHg). Here, we aimed (i) to study the dispersion of Hg in four reservoirs located downstream of a chlor-alkali plant along the Olt River (Romania) and (ii) to track the activity of bacterial functional genes involved in Hg methylation. Total Hg (THg) concentrations in water and sediments decreased successively from the initial reservoir to downstream reservoirs. Suspended fine size particles and seston appeared to be responsible for the transport of THg into downstream reservoirs, while macrophytes reflected the local bioavailability of Hg. The concentration and proportion of MeHg were correlated with THg, but were not correlated with bacterial activity in sediments, while the abundance of hgcA transcript correlated with organic matter and Cl- concentration, indicating the importance of Hg bioavailability in sediments for Hg methylation. Our data clearly highlights the importance of considering Hg contamination as a legacy pollutant since there is a high risk of continued Hg accumulation in food webs long after Hg-cell phase out.

Revegetation is one practical application of science that should ideally aim to combine ecology with evolution to maximise biodiversity and ecosystem outcomes. The strict use of locally sourced seed in revegetation programs is widespread and is based on the expectation that populations are locally adapted. This practice does not fully integrate two global drivers of ecosystem change and biodiversity loss: habitat fragmentation and climate change. Here, we suggest amendments to existing strategies combined with a review of alternative seed-sourcing strategies that propose to mitigate against these drivers. We present a provenancing selection guide based on confidence surrounding climate change distribution modelling and data on population genetic and/or environmental differences between populations. Revegetation practices will benefit from greater integration of current scientific developments and establishment of more long-term experiments is key to improving the long-term success. The rapid growth in carbon and biodiversity markets creates a favourable economic climate to achieve these outcomes.